1. Field of the Invention
This invention relates to a waste water treating process using a biomass of anaerobic microorganisms.
2. Description of Information Disclosures
Anaerobic processes are known for treating waste water containing organic pollutants to decompose the organic pollutants to carbon dioxide and methane and, thereby, produce a treated waste water which is environmentally acceptable.
U.S. Pat. No. 4,351,729 discloses subjecting waste water containing organic pollutants to anaerobic biological treatment.
U.S. Pat. No. 4,315,823 discloses adding an alkaline material such as sodium hydroxide to an anaerobic filter for treatment of acidic waste water to neutralize the acids. The proportion of sodium ion in the total feed to the anaerobic filter is usually not above 4 g/l (i.e., 4000 mg/l).
It has been disclosed that sodium inhibits anaerobic microorganisms. See, for example, McCarty and McKinney "Volatile Acid Toxicity in Anaerobic Digestion", Journal of Water Pollution Control Fed., Vol. 33, No. 3, pages 223-232, 1961; and Kugelman and Chin, "Toxicity, Synergism and Antagonism in Anaerobic Waste Treatment Processes", Advances in Chemistry Series V.105, American Chemical Society, 1971.
It has now been found that waste water comprising organic pollutants and a high concentration of salts, such as water separated from crude oil at the production well, may be treated with a biomass of anaerobic microorganisms to decompose the organic pollutants while minimizing the inhibition of the microorganisms, if the microorganisms are preconditioned to these salts prior to contacting the microorganisms with the waste water comprising the high concentration of salts.